#pragma once

#include<iostream>
#include<assert.h>
using namespace std;

class Date
{
	friend ostream& operator<<(ostream& out, const Date& d);
	friend istream& operator>>(istream& in, Date& d);

public:
	Date(int year = 1900, int month = 1, int day = 1);

	void Print() const;

	bool CheckDate() const
	{
		if (_month < 1 || _month >12
			|| _day < 1 || _day > GetMonthDay(_year, _month))
		{
			return false;
		}
		else
		{
			return true;
		}
	}

	int GetMonthDay(int year, int month) const
	{
		assert(month > 0 && month < 13);

		static int MonthDayArray[13] = { -1,31,28,31,30,31,30,31,31,30,31,30,31 };

		if (month == 2 && (year % 4 == 0 && year % 100 != 0) || (year % 400 == 0))
		{
			return 29;
		}

		return MonthDayArray[month];
	}

	bool operator<(const Date& d) const;
	bool operator>(const Date& d) const;
	bool operator<=(const Date& d) const;
	bool operator>=(const Date& d) const;
	bool operator==(const Date& d) const;
	bool operator!=(const Date& d) const;

	Date& operator+=(int day);
	Date operator+(int day) const;

	Date& operator-=(int day);
	Date operator-(int day) const;

	// ++d
	Date& operator++();
	// d++
	Date operator++(int);

	// --d
	Date& operator--();
	// d--
	Date operator--(int);

	int operator-(const Date& d) const;

private:
	int _year;
	int _month;
	int _day;
};

ostream& operator<<(ostream& out, const Date& d);
istream& operator>>(istream& in, Date& d);